In Emacs 29.1 the point-at-bol and point-at-eol functions are obsolete. This removes the following warnings when compiling the file:

    In dockerfile-indent-line-function:
    dockerfile-mode.el:159:41: Warning: ‘point-at-bol’ is an obsolete function (as
        of 29.1); use ‘line-beginning-position’ or ‘pos-bol’ instead.
    dockerfile-mode.el:163:37: Warning: ‘point-at-eol’ is an obsolete function (as
        of 29.1); use ‘line-end-position’ or ‘pos-eol’ instead.
    dockerfile-mode.el:164:32: Warning: ‘point-at-eol’ is an obsolete function (as
        of 29.1); use ‘line-end-position’ or ‘pos-eol’ instead.
    dockerfile-mode.el:166:27: Warning: ‘point-at-bol’ is an obsolete function (as
        of 29.1); use ‘line-beginning-position’ or ‘pos-bol’ instead.

It is safe to use these new functions as they were introduced as of Emacs 20.